Why is a horse gender neutral while other animals aren't? (i.e. Het vs De)
Het paard, het varken (pig), het schaap (sheep), het konijn (rabbit), there's no real reason for it apart from that to Dutch people 'de' in front of these words just sounds 'wrong' :)
How would i say the horse IS DRINKING instead of the horse drinks?
I think it's the same in Dutch.
I translated this to be "the horse drank water" is this incorrect?
Yes, because "drinkt" is present tense (specifically, third person singular present), not past tense. So you need to translate this sentence as "The horse drinks/is drinking water".
Drinkt is used for both 'drinks' and 'is drinking'? I will only know the difference by context?